1. Field of the Invention
This invention relates generally to framing systems for building structures, and more particularly to improved roll formed metal framing members.
2. Description of Prior Art
Lightweight rolled metal double channel sections welded to form "I" shaped and "C" shaped plates have been available for almost a century, but contain excess metal and are so labor intensive to manufacture that they have not been competitive except in special situations. Roll formed steel framing members having "C" shaped channel sections for concealed construction in the form in which I originally designed them, and in modified forms, are presently being used world-wide but due to high costs have been primarily limited to commercial structures. These sections also contain excess metal for home construction and do not have provision for supportively receiving fastening devices driven into their cross sectional ends, resulting in overpriced and labor intensive products when used as conventional members in homes and other light construction.
That these framing members have excess metal is dramatically demonstrated when a metal frame member is used under axial loading conditions. A computation is performed to determine the amount of the net cross section that may be considered in establishing its load bearing capability. As much as twenty two percent (22%) of the metal included in the net cross sectional area of these sections is excluded in calculating this capability or "Q" column value and is essentially wasted material.
A further deficiency of these sections is that they contain no visual measuring means to indicate the proper spacing of the members to which they are to be joined. Moreover, when threaded fasteners are used to fasten these sections together, the heads of the screws protrude from the plate flange surface which often breaks the drywall placed there against.
Representative of the prior art of metal framing systems are my previous U.S. Pat. Nos. 2,664,179, 2,736,403, 3,129,792, and 3,849,961.
The present invention provides a continuously roll formed metal framing member formed with a web and two flanges extending from the two edges of the web. The distal edges of the flanges are roll formed to provide multi-function edge recesses which will be available for fastening to the flange surface flange recess or to the end of the member, regardless of the length at which it is cut. The improved member of this invention may be further formed by providing additional fastener receiving recesses in the ends of the member at the inside corners between the web and flanges. The web may be expanded and the center portion of the web may also be corrugated before expanding for increased stiffness and formability by extending the corrugations into the unexpanded outer portions of the web. Those members to be used as horizontally disposed plates include two spaced apart rows of holes provided in the unexpanded outer portions of the web for the placing of fasteners therethrough. The holes and rows of holes are spaced at preselected intervals and adapted to provide the visual indicia for the location of studs and joists and, e.g. the center line of an alternate shaped set of four holes, two in each row, matching the end fastener recess pattern in the attached members is provided every eight inches so that two intervals will provide spacing of sixteen inches and three intervals will provide spacing of twenty four inches. Composite members are also formed using wire webs with rolled flanges. Special configurations are provided for truss chords and struts (not shown) which may be conveniently assembled at the construction site and are also provided with preselected punched holes along the length of the webs for lapped truss chord and strut attachment and for assembly into trusses with slopes from zero to ninety degrees.